1. Field of the Invention
The present invention relates to an apparatus and method for controlling an auto-zooming operation. More particularly the present invention relates to an apparatus and method for controlling an auto-zooming operation of a mobile terminal such as a camcorder phone, which can automatically adjust the size of a target subject captured by the mobile terminal to be a predetermined size irrespective of a distance between the mobile terminal and the target object.
2. Description of the Related Art
A camcorder, which is an example of an image capturing device, can function as a general camera for photographing a target object and can also function as a video recorder for recording a series of events.
There is a need for the image capturing device such as a camcorder to perform appropriate exposure, focusing, and zooming operations in order to sufficiently reconstruct and satisfactorily capture a momentary image of the target object. The focusing and digital-zooming operations of the aforementioned image capturing device such as a camcorder will hereinafter be described.
A variety of focusing methods have been widely used for measuring a distance between a camera and a target object. A system for accomplishing this can be classified into an active system and a passive system. Examples of active systems include an ultrasound focusing system and an infrared focusing system. Passive systems include a contrast recognition method and an eye-controlled auto-focus system.
The active system will hereinafter be described. The ultrasound focusing system counts a time delay from an ultrasound transmission time to its echo reception time in order to calculate a distance between a camera and a target object, and automatically adjusts a lens based on the distance in order to perform a focus control operation. The infrared focusing system moves a lens to enable the infrared beam to be reflected from a target object in a scanning mode, and performs a focus control operation using a trigonometric measurement scheme.
The passive system will hereinafter be described. The contrast recognition method projects the same image on a mirror interoperable with a non-stationary lens and a fixed lens using a visitronic module, adds the images projected on the mirror and the fixed lens, focuses the images on the fixed lens, and closes a shutter. The eye-controlled auto-focus system horizontally installs five focusing points in a viewfinder, and enables a user such as a cameraman to select predetermined focusing points associated with a desired target object where the camera will be focused when the user views the target objects.
The user performs a focusing operation using the aforementioned auto-focus function during a moving image capture time, and presses a zoom-in key and a zoom-out key to capture an image of a main target object currently in motion, such that the size of the main target object can be maintained at a predetermined size during the image capture time.
However, the aforementioned conventional image capture device such as a camcorder cannot automatically control a screen image configuration. Thus, there is the conventional image capture device has a disadvantage in that the user must unavoidably move from a current position to another position whenever the main target object moves to another position. In other words, the user must maintain the same distance between the camera and the main target object. Also, the conventional image capture device has difficulty in detecting the image of the target object while maintaining the same distance between the camera and the target object even though the user directly moves to another position.
Furthermore, the conventional image capture device results in greater inconvenience for the user who presses a zoom-in key and a zoom-out key to maintain a predetermined distance between the camera and the target object, and has difficulty in consistently maintaining the size of a captured main target object while maintaining the predetermined distance between the camera and the target object using the zoom-in and zoom-out keys.